Woods Hole drones find a million penguins

By Christine LegereThe Cape Cod Times

Monday

Mar 12, 2018 at 7:55 AMMar 12, 2018 at 10:04 AM

WOODS HOLE — The discovery of a “supercolony” of Adelie penguins, nesting on a string of islands off the Antarctic Peninsula’s northern tip, has changed a previous assumption that the numbers of the small birds are declining.

In fact, an excursion to the Danger Islands added a whopping 1.5 million to their population tally.

A team of researchers led by Woods Hole Oceanographic Institution planned the trip to the Danger Islands, prompted by NASA satellite photos that showed the rocky surface of the chain blanketed in reddish-colored guano.

“We knew it was birds and probably penguins, but it was hard to know how many were there,” said Stephanie Jenouvrier, a seabird ecologist at Woods Hole, who studies the impact of climate change on seabirds, primarily in the Antarctic.

The penguin population on the Danger Islands has gone essentially undetected due to the remoteness of the chain and the choppy waters, filled with thick sea ice, that surround them.

A 10-member team of researchers made the trip to the Antarctic in 2015, arriving in December, which is summer there and breeding season for penguins.

“The Danger Islands are a very hard place to visit because there is so much sea ice around them for so much of the year,” said Michael Polito, Louisiana State University professor and guest investigator at Woods Hole. “Getting to the islands by ship took many days and required us to avoid ice and strong currents along the way.”

The group traveled from the Falkland Islands to the Danger Islands on the steel-hulled yacht Hans Hansson, where they remained at night. During the day, scientists would access the various islands by Zodiac vessel.

“Once on the islands, we had to wait until there was very little wind so we could fly a quadcopter drone to take pictures of the nesting penguins from above,” Polito said. “We then used a computer program to analyze these pictures and count the number of nests on each island.”

They were surprised to ultimately count 751,527 penguin pairs — or 1.5 million individuals — making the Danger Islands a major hot spot for the Adelie.

The team published its discovery of the supercolony of the 2-foot tall-Adelies earlier this month in the journal Scientific Research.

Adelie penguins are almost exclusively found in the southern hemisphere. They live in the water, but return to land to breed in large colonies. Nests are constructed of stones. Female penguins lay one or two eggs, then remain on land for several months raising the chicks.

“We knew penguins were there, but nobody had figured how many there were; that was the big surprise,” said Hanumant Singh, a professor at Northeastern University and the Woods Hole group’s expert who designed the aerial drones used to take the photos on the Antarctic trip.

The magnetic pull of the poles and the impact of the cold temperatures were both challenges the location presented for the equipment, Singh said.

The drones and cameras performed well, and the images were later run through the computer to calculate the number of penguins on the islands.

Hand counts of the images were also done and compared to the computer counts, Singh said.

The supercolony that scientists found on the Danger Islands contrasts sharply with what’s happening to the Adelie population on the west coast of the Antarctic Peninsula, where the numbers are declining.

The west side is more accessible, Jenouvrier said, with its waters frequented by fishing vessels catching krill, and tourist boats.

“The population there has been declining since the 1980s,” Jenouvrier said.

Climate conditions also differ on the west coast. “Temperature has been increasing and sea ice is in decline,” the scientist said. Those changes are the result of ozone damage done decades ago.

“We think the Danger Islands population is stable,” Jenouvrier said. “This study is important. We found so many penguins in one area that’s been buffered from climate change. It provides a benchmark for what happens in the future.”

The question of why so many Adelie live on the Danger Islands will be considered as study continues, Jenouvrier said. Their presence could be related to the abundance of sea ice or the supply of food.

A camera recording real-time activity was left on the islands, and images were to be relayed back via satellite. The relay didn’t work, but the camera was recently retrieved. Scientists will look at the images to learn more about the patterns of the Adelie penguins.

The discovery of the Adelie supercolony will also help support a proposal to create Marine Protected Areas near the Antarctic Peninsula.

Also collaborating on the study were Heather Lynch, Alex Borowicz, Philip McDowall, Casey Youngflesh, Mathew Schwaller and Rachael Herman from Stony Brook University; Thomas Sayre-McCord from Woods Hole Oceanographic Institution and MIT; Stephen Forrest and Melissa Rider from Antarctic Resource Inc.; Thomas Hart from Oxford University and Gemma Clucas from the University of Southampton.

Follow Christine Legere on Twitter: @ChrisLegereCCT.

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